[PATCH v6 2/2] input: keypad: add new keypad driver for MA35D1

Ming-Jen
2025-01-09T00:26:36Z

Adds a new keypad driver for the MA35D1 platform.
The driver supports key scanning and interrupt handling.

Signed-off-by: Ming-jen Chen <mjchen0829@gmail.com>
---
drivers/input/keyboard/Kconfig | 10 +
drivers/input/keyboard/Makefile | 1 +
drivers/input/keyboard/ma35d1_keypad.c | 387 +++++++++++++++++++++++++
3 files changed, 398 insertions(+)
create mode 100644 drivers/input/keyboard/ma35d1_keypad.c

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index 721ab69e84ac..d7c0d0f4a88d 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -797,4 +797,14 @@ config KEYBOARD_CYPRESS_SF
To compile this driver as a module, choose M here: the
module will be called cypress-sf.

+config KEYBOARD_MA35D1
+ tristate "Nuvoton MA35D1 keypad driver"
+ depends on ARCH_MA35 || COMPILE_TEST
+ select INPUT_MATRIXKMAP
+ help
+ Say Y here if you want to use Nuvoton MA35D1 keypad.
+
+ To compile this driver as a module, choose M here: the
+ module will be called ma35d1-keypad.
+
endif
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 1e0721c30709..9b858cdd1b6b 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -70,3 +70,4 @@ obj-$(CONFIG_KEYBOARD_TEGRA) += tegra-kbc.o
obj-$(CONFIG_KEYBOARD_TM2_TOUCHKEY) += tm2-touchkey.o
obj-$(CONFIG_KEYBOARD_TWL4030) += twl4030_keypad.o
obj-$(CONFIG_KEYBOARD_XTKBD) += xtkbd.o
+obj-$(CONFIG_KEYBOARD_MA35D1) += ma35d1_keypad.o
diff --git a/drivers/input/keyboard/ma35d1_keypad.c b/drivers/input/keyboard/ma35d1_keypad.c
new file mode 100644
index 000000000000..befae383eaa3
--- /dev/null
+++ b/drivers/input/keyboard/ma35d1_keypad.c
@@ -0,0 +1,387 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * MA35D1 keypad driver
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/interrupt.h>
+#include <linux/input.h>
+#include <linux/platform_device.h>
+#include <linux/input/matrix_keypad.h>
+#include <linux/clk.h>
+#include <linux/of.h>
+#include <linux/io.h>
+#include <linux/bitops.h>
+#include <linux/pm_wakeirq.h>
+
+/* Keypad Interface Registers */
+#define KPI_CONF 0x00
+#define KPI_3KCONF 0x04
+#define KPI_STATUS 0x08
+#define KPI_RSTC 0x0C
+#define KPI_KEST 0x10
+#define KPI_KPE0 0x18
+#define KPI_KPE1 0x1C
+#define KPI_KRE0 0x20
+#define KPI_KRE1 0x24
+#define KPI_PRESCALDIV 0x28
+
+/* KPI_CONF - Keypad Configuration Register */
+#define KROW GENMASK(30, 28) /* Keypad Matrix ROW number */
+#define KCOL GENMASK(26, 24) /* Keypad Matrix COL Number */
+#define DB_CLKSEL GENMASK(19, 16) /* De-bounce sampling cycle selection */
+#define PRESCALE GENMASK(15, 8) /* Row Scan Cycle Pre-scale Value */
+#define WAKEUP BIT(5) /* Lower Power Wakeup Enable */
+#define INTEN BIT(3) /* Key Interrupt Enable Control */
+#define RKINTEN BIT(2) /* Release Key Interrupt Enable */
+#define PKINTEN BIT(1) /* Press Key Interrupt Enable Control */
+#define ENKP BIT(0) /* Keypad Scan Enable */
+
+/* KPI_STATUS - Keypad Status Register */
+#define PKEY_INT BIT(4) /* Press key interrupt */
+#define RKEY_INT BIT(3) /* Release key interrupt */
+#define KEY_INT BIT(2) /* Key Interrupt */
+#define RST_3KEY BIT(1) /* 3-Keys Reset Flag */
+#define PDWAKE BIT(0) /* Power Down Wakeup Flag */
+
+#define KEY_EVENT_BITS 64
+
+#define NUM_SETTINGS 12
+#define PRE_SCALE_MAX 256
+#define PRE_SCALE_DIV_MAX 256
+
+static const unsigned int debounce_values[NUM_SETTINGS] = {
+ 0, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192
+};
+
+static const unsigned int debounce_register[NUM_SETTINGS] = {
+ 0x0, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xA, 0xB, 0xC, 0xD
+};
+
+struct ma35d1_keypad {
+ struct clk *clk;
+ struct input_dev *input_dev;
+ void __iomem *mmio_base;
+ int irq;
+ u32 kpi_row;
+ u32 kpi_col;
+ u32 debounce_val;
+ u32 pre_scale;
+ u32 pre_scale_div;
+};
+
+static void ma35d1_keypad_scan_matrix(struct ma35d1_keypad *keypad, unsigned int status)
+{
+ struct input_dev *input_dev = keypad->input_dev;
+ u32 row_shift = get_count_order(keypad->kpi_col);
+ u32 *keymap = input_dev->keycode;
+ u32 code, key, index;
+ u32 key_event[4];
+ u64 pressed_keys = 0, released_keys = 0;
+
+ /* Read key event status */
+ key_event[0] = readl(keypad->mmio_base + KPI_KPE0);
+ key_event[1] = readl(keypad->mmio_base + KPI_KPE1);
+ key_event[2] = readl(keypad->mmio_base + KPI_KRE0);
+ key_event[3] = readl(keypad->mmio_base + KPI_KRE1);
+
+ /* Clear key event status */
+ writel(key_event[0], (keypad->mmio_base + KPI_KPE0));
+ writel(key_event[1], (keypad->mmio_base + KPI_KPE1));
+ writel(key_event[2], (keypad->mmio_base + KPI_KRE0));
+ writel(key_event[3], (keypad->mmio_base + KPI_KRE1));
+
+ pressed_keys = key_event[0] | ((u64)key_event[1] << 32);
+ released_keys = key_event[2] | ((u64)key_event[3] << 32);
+
+ /* Process pressed keys */
+ for_each_set_bit(index, (const unsigned long *)&pressed_keys, KEY_EVENT_BITS) {
+ code = MATRIX_SCAN_CODE(index / 8, (index % 8), row_shift);
+ key = keymap[code];
+
+ input_event(input_dev, EV_MSC, MSC_SCAN, code);
+ input_report_key(input_dev, key, 1);
+ }
+
+ /* Process released keys */
+ for_each_set_bit(index, (const unsigned long *)&released_keys, KEY_EVENT_BITS) {
+ code = MATRIX_SCAN_CODE(index / 8, (index % 8), row_shift);
+ key = keymap[code];
+
+ input_event(input_dev, EV_MSC, MSC_SCAN, code);
+ input_report_key(input_dev, key, 0);
+ }
+
+ input_sync(input_dev);
+}
+
+static irqreturn_t ma35d1_keypad_interrupt(int irq, void *dev_id)
+{
+ struct ma35d1_keypad *keypad = dev_id;
+ unsigned int kstatus;
+
+ kstatus = readl(keypad->mmio_base + KPI_STATUS);
+
+ if (kstatus & (PKEY_INT | RKEY_INT)) {
+ ma35d1_keypad_scan_matrix(keypad, kstatus);
+ } else {
+ if (kstatus & PDWAKE)
+ writel(PDWAKE, (keypad->mmio_base + KPI_STATUS));
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int ma35d1_keypad_open(struct input_dev *dev)
+{
+ struct ma35d1_keypad *keypad = input_get_drvdata(dev);
+ u32 val, config;
+
+ val = RKINTEN | PKINTEN | INTEN | ENKP;
+ val |= FIELD_PREP(KCOL, (keypad->kpi_col - 1)) | FIELD_PREP(KROW, (keypad->kpi_row - 1));
+
+ config = FIELD_PREP(PRESCALE, (keypad->pre_scale - 1)) |
+ FIELD_PREP(DB_CLKSEL, keypad->debounce_val);
+
+ val |= config;
+
+ writel(val, keypad->mmio_base + KPI_CONF);
+ writel((keypad->pre_scale_div - 1), keypad->mmio_base + KPI_PRESCALDIV);
+
+ return 0;
+}
+
+static void ma35d1_keypad_close(struct input_dev *dev)
+{
+ struct ma35d1_keypad *keypad = input_get_drvdata(dev);
+ u32 val;
+
+ val = readl(keypad->mmio_base + KPI_KPE0) & ~ENKP;
+ writel(val, keypad->mmio_base + KPI_CONF);
+}
+
+static int ma35d1_parse_dt(struct ma35d1_keypad *keypad, u32 debounce_ms, u32 scan_interval)
+{
+ u32 clk_rate = clk_get_rate(keypad->clk);
+ u32 min_diff = debounce_values[NUM_SETTINGS - 1];
+ u32 i, clk_cycles, diff, p, d;
+ u32 best_diff = 0xffff;
+
+ /* Calculate debounce cycles */
+ clk_cycles = clk_rate * debounce_ms / 1000;
+
+ keypad->debounce_val = debounce_register[NUM_SETTINGS - 1];
+
+ for (i = 0; i < NUM_SETTINGS; i++) {
+ diff = abs((s32)(clk_cycles - debounce_values[i]));
+ if (diff < min_diff) {
+ min_diff = diff;
+ keypad->debounce_val = debounce_register[i];
+ }
+ }
+
+ /* Find scan time setting */
+ clk_cycles = clk_rate * scan_interval / 1000;
+ clk_cycles = clk_cycles / keypad->kpi_row;
+
+ if (clk_cycles == 0) {
+ keypad->pre_scale = 1;
+ keypad->pre_scale_div = 1;
+ } else if (clk_cycles >= PRE_SCALE_MAX * PRE_SCALE_DIV_MAX) {
+ keypad->pre_scale = PRE_SCALE_MAX;
+ keypad->pre_scale_div = PRE_SCALE_DIV_MAX;
+ } else {
+ for (p = 1; p <= PRE_SCALE_MAX; p++) {
+ d = (clk_cycles + (p / 2)) / p;
+
+ if (d > 0 && d <= PRE_SCALE_DIV_MAX) {
+ diff = abs((s32)(p * d) - clk_cycles);
+
+ if (diff < best_diff) {
+ best_diff = diff;
+ keypad->pre_scale = p;
+ keypad->pre_scale_div = d;
+
+ if (diff == 0)
+ break;
+ }
+ }
+ }
+ }
+
+ /*
+ * Hardware Limitation:
+ * Due to the hardware design, the keypad debounce time must not exceed
+ * half of the row scan time.
+ *
+ * The row scan time is determined by the formula:
+ * Row Scan Time = pre_scale * pre_scale_div
+ *
+ * Therefore, the debounce time must satisfy the following condition:
+ * Debounce Time < (Row Scan Time / 2)
+ *
+ * For example:
+ * If pre_scale = 64, pre_scale_div = 32,
+ * then Row Scan Time = 64 * 32 = 2048 keypad clock.
+ * Hence, the maximum allowable debounce time is 1024 keypad clock.
+ */
+
+ if (keypad->debounce_val >= (keypad->pre_scale * keypad->pre_scale_div) / 2)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int ma35d1_keypad_probe(struct platform_device *pdev)
+{
+ struct ma35d1_keypad *keypad;
+ struct input_dev *input_dev;
+ struct resource *res;
+ u32 debounce, scan_interval;
+ int error = 0;
+
+ keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
+ if (!keypad)
+ return -ENOMEM;
+
+ input_dev = devm_input_allocate_device(&pdev->dev);
+ if (!input_dev)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+
+ keypad->mmio_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(keypad->mmio_base))
+ return dev_err_probe(&pdev->dev, PTR_ERR(keypad->mmio_base),
+ "failed to remap I/O memor\n");
+
+ keypad->irq = platform_get_irq(pdev, 0);
+ if (keypad->irq < 0) {
+ dev_err(&pdev->dev, "failed to get IRQ\n");
+ return keypad->irq;
+ }
+
+ keypad->clk = devm_clk_get_enabled(&pdev->dev, NULL);
+ if (IS_ERR(keypad->clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(keypad->clk), "failed to get core clk\n");
+
+ error = matrix_keypad_parse_properties(&pdev->dev, &keypad->kpi_row, &keypad->kpi_col);
+ if (error) {
+ dev_err(&pdev->dev, "failed to parse keypad params\n");
+ return error;
+ }
+
+ error = matrix_keypad_build_keymap(NULL, NULL, keypad->kpi_row, keypad->kpi_col,
+ NULL, input_dev);
+ if (error) {
+ dev_err(&pdev->dev, "failed to build keymap\n");
+ return error;
+ }
+
+ keypad->input_dev = input_dev;
+ input_dev->name = pdev->name;
+ input_dev->id.bustype = BUS_HOST;
+ input_dev->open = ma35d1_keypad_open;
+ input_dev->close = ma35d1_keypad_close;
+ input_dev->dev.parent = &pdev->dev;
+
+ error = device_property_read_u32(&pdev->dev, "debounce-delay-ms", &debounce);
+ if (error) {
+ dev_err(&pdev->dev, "failed to acquire 'debounce-delay-ms'\n");
+ return error;
+ }
+
+ error = device_property_read_u32(&pdev->dev, "scan-interval-ms", &scan_interval);
+ if (error) {
+ dev_err(&pdev->dev, "failed to acquire 'scan-interval'\n");
+ return error;
+ }
+
+ error = ma35d1_parse_dt(keypad, debounce, scan_interval);
+ if (error) {
+ dev_err(&pdev->dev, "keypad dt params error\n");
+ return error;
+ }
+
+ __set_bit(EV_REP, input_dev->evbit);
+ input_set_drvdata(input_dev, keypad);
+ input_set_capability(input_dev, EV_MSC, MSC_SCAN);
+
+ error = devm_request_irq(&pdev->dev, keypad->irq, ma35d1_keypad_interrupt,
+ IRQF_NO_SUSPEND, pdev->name, keypad);
+ if (error) {
+ dev_err(&pdev->dev, "failed to request IRQ\n");
+ return error;
+ }
+
+ platform_set_drvdata(pdev, keypad);
+ device_init_wakeup(&pdev->dev, 1);
+
+ error = dev_pm_set_wake_irq(&pdev->dev, keypad->irq);
+ if (error) {
+ dev_err(&pdev->dev, "failed to enable irq wake\n");
+ return error;
+ }
+
+ error = input_register_device(input_dev);
+ if (error) {
+ dev_err(&pdev->dev, "failed to register input device\n");
+ return error;
+ }
+
+ return 0;
+}
+
+static void ma35d1_keypad_remove(struct platform_device *pdev)
+{
+ struct ma35d1_keypad *keypad = platform_get_drvdata(pdev);
+
+ input_unregister_device(keypad->input_dev);
+}
+
+static int ma35d1_keypad_suspend(struct device *dev)
+{
+ struct ma35d1_keypad *keypad = dev_get_drvdata(dev);
+
+ if (device_may_wakeup(dev))
+ writel(readl(keypad->mmio_base + KPI_CONF) | WAKEUP, keypad->mmio_base + KPI_CONF);
+
+ return 0;
+}
+
+static int ma35d1_keypad_resume(struct device *dev)
+{
+ struct ma35d1_keypad *keypad = dev_get_drvdata(dev);
+
+ if (device_may_wakeup(dev))
+ writel(readl(keypad->mmio_base + KPI_CONF) & ~(WAKEUP),
+ keypad->mmio_base + KPI_CONF);
+
+ return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(ma35d1_pm_ops, ma35d1_keypad_suspend, ma35d1_keypad_resume);
+
+static const struct of_device_id ma35d1_kpi_of_match[] = {
+ { .compatible = "nuvoton,ma35d1-keypad"},
+ {},
+};
+MODULE_DEVICE_TABLE(of, ma35d1_kpi_of_match);
+
+static struct platform_driver ma35d1_keypad_driver = {
+ .probe = ma35d1_keypad_probe,
+ .remove = ma35d1_keypad_remove,
+ .driver = {
+ .name = "ma35d1-keypad",
+ .pm = pm_sleep_ptr(&ma35d1_pm_ops),
+ .of_match_table = ma35d1_kpi_of_match,
+ },
+};
+module_platform_driver(ma35d1_keypad_driver);
+
+MODULE_AUTHOR("Ming-Jen Chen");
+MODULE_DESCRIPTION("MA35D1 Keypad Driver");
+MODULE_LICENSE("GPL");
--
2.25.1